Self-assembly of block copolymers (BCPs) in thin films provides a large area, high throughput route to creating dense nano-structures with length scales not easily achievable by traditional lithography processes. BCP lithography is widely accepted by the industry as one of the solutions to achieve sub 20 nm nodes. While there are many approaches to controlling domain morphology in BCP lithography, the use of surface modifying random copolymers as neutral layers is commonly employed.
Unfortunately, while the neutral copolymer chemistry is essential to control domain orientation in BCPs, the neutral layers constitute an additional layer to bore through during BCP template formation and leave organic residues on the substrate after nanopatterning. Moreover, the strong reactive ion etchants needed to remove the organic BCP template structures and the underlying neutral layers can damage the underlying substrate.